The invention relates generally to interior lighting for residences, businesses and other locations, and, in particular, to energy efficient fluorescent lighting.
The 1990""s have seen a renewed national commitment to saving energy. However, in many areas residential lighting energy conservation efforts have not generally delivered their full potential. While most end use areas have seen 30 to 50 percent efficiency improvements, numerous resources remain unmined. Moreover, lighting efficiency has been, in places, clumsily implemented and consequently, has not been well received by consumers. Residential lighting in particular, is a microcosm of these larger trends.
Each year in the U.S. about 145 billion kilowatt-hours of energy are used to light homes, at a cost of 10 billion dollars, and resulting in the emission of approximately 140 million tons of carbon dioxide. Promoting and installing more efficient residential light sources, fixtures, and controls can significantly reduce these numbers. The compact fluorescent lamp (CFL) is the most dramatic example of such a technology, offering a 75 percent increase in total lamp lumens per watt over the ubiquitous general service incandescent lamp (A-lamp). Unfortunately, actual applications of CFLs often fail to deliver on promises of equivalent light quality, quantity, and distribution, at comparable cost to traditional lighting.
One of the most popular residential lighting fixtures is the table lamp fixture. These use almost exclusively 60-100 watt incandescent lamps. But they do not offer distribution control.
The current perceptions of CFL table lamps are that they are expensive, not bright enough, prone to failure, and don""t look good. This results in widespread consumer rejection. Thus, of the large potential market for residential table lamps, 90 million homes with three plus table lamps per home, CFLs have attained only about 1 percent market share or less.
Of all CFL table lamps, most are screw-based retrofits (Edison sockets); almost none are pin-based hardwired fixtures. Most common are lamps with single, vertically oriented CFLs, e.g. 9-40 watt twin, quad and multi-tube configurations. Some of these are encapsulated in a plastic capsule or globe. The vertical orientation is inefficient in that it directs flux towards the shade. Single lamps offer no control of light distribution out of the fixture. Single planar CFL lamps, e.g. circline and 2D CFLs, are better inside shaded table lamp fixtures, but control is only available through level/intensity control with electronic ballasts.
There is a commercial hardwired table lamp configuration using three twin-tube CFLs arranged radially in a vertical orientation. Switching one, two, and three lamps offers three level intensity control, but there is no control over light distribution.
Multi-lamp incandescent table and floor lamps have traditionally offered level intensity control, typically in dual or triple lamp configurations, usually arranged radially around the center, or with three level switching and/or dimming of a single lamp, e.g. a 50-100-150 W A-lamp. However, control over distribution of light out of the fixture into the room has not generally been provided.
A significant feature of a new lighting fixture based on any type of lamp would be control of light distribution out of the lamp, i.e. the user can readily select and vary the light distribution to meet changing needs. For example, under some conditions direct lighting is needed, while under other conditions indirect lighting is desired. Thus a light fixture which allows a user to readily switch between direct lighting, indirect lighting, or both, would be highly advantageous since the lamp would deliver most of the light where it is needed. Coupled with efficient light sources, e.g. CFLs, tremendous lighting efficiency can be achieved. Unfortunately, present lamps are generally configured with a fixed light output distribution pattern which cannot be changed by the user.
Therefore, it is desirable to provide new lamp fixture configurations for CFL based lamps which take advantage of the great advances in CFL technology made in recent years and which allow easy selection and control of light distribution. High quality phosphors and electronic ballasts produced in the 1990""s and the many new shapes, sizes, and colors available provide a lot of flexibility in lighting options. However, the integration of CFLs into table lamps has primarily involved trying to make CFLs behave like incandescent lamps instead of taking advantage of the inherent characteristics of the CFLs. The new design should have high performance, flexibility in control, and provide lots of light for user amenities. A new CFL table lamp fixture design with these features could capture a significant market share. At present, with 90 million homes having three plus table lamps per home at a cost of about $75.00 plus per fixture, with a present CFL market share of less than one percent, there is huge potential for market growth with an efficient CFL fixture. The market potential is further expanded when the lighting system design is applied to table lamps for offices, hotels and other locations, and floor lamps for all these locations.
Aesthetic appearance is also an important factor in lamp design and selection. While torchieres, in which lamps are enclosed in reflectors without shades, are suitable in some situations, lamps with luminous or translucent shades are preferred in many environments. However, shaded lamps often suffer from hot spots and other nonuniform shade illumination patterns. It would be highly desirable from an aesthetic view to have uniform shade illumination.
In addition, the current electrical power problems in California dramatically demonstrate the need for greater electrical efficiency and electrical energy conservation. The state is faced with inadequate supply to meet the growing demand, and is under a constant threat of rolling blackouts. The electrical utility companies have been forced to buy electricity on the spot market at astronomical cost, and are facing bankruptcy since they cannot pass the costs on to the users. If the costs are passed on to the consumer, many will struggle to pay their utility bills.
Interior lighting is one area where significant electrical energy can be saved if efficient lighting systems are used. Coupled with high performance, lighting quality, and aesthetics, such lighting systems should gain widespread and ready market acceptance.
Accordingly, it is an object of the invention to provide an improved lighting fixture design for CFL based table and floor lamps, for broad residential, hospitality, and commercial lighting applications.
It is also an object of the invention to provide a lighting fixture geometry for table and floor lamps based on CFLs, that produces controlled light distribution, controlled light intensity, lots of light, and other user amenities.
It is another object of the invention to provide a table or floor lamp with dynamically controlled lighting distribution and with a luminous or translucent shade which is uniformly illuminated.
The invention is a lighting fixture, and a complete table or floor lamp including the fixture, in which two lamps are mounted in a spaced apart vertical relation (i.e. one lamp above the other) with a reflective septum mounted in a substantially horizontal orientation between the two lamps. Additional lamps may also be added above and/or below the septum so that there is at least one lamp above the septum and at least one lamp below the septum. The two lamps are preferably compact fluorescent lamps (CFLs), and more preferably are planar CFLs, but other lamps could also be used. The lamps are preferably mounted in a substantially horizontal orientation. The lamps are preferably circular in geometry, but other geometries can also be used. The lamps and separating reflective septum are also surrounded by a lateral shade which is open at the top and bottom. A user control switch and dimmer allows the user to control lamp output light distribution in three modes: down light only, up light only, or a combination of down light and up light. The control switch also allows user control of light level in each of the lamps. The reflective septum maintains the up/down or combination distribution and also controls stray light and increases efficiency. Thus, the lamp produces a lot of light in a selectable or easily controllable distribution. The optical relationship (geometry) between the lamps, reflective septum, and shade can be designed to maintain even shade luminance while maximizing fixture efficiency and control. Color control may also be achieved by using different color temperature lamps. For example, users may want to have predominantly high color temperature lighting directed upwards (for indirect lighting) and low color temperature lighting directed downwards (for direct lighting). The dual CFL fixture may be used in both table lamps and floor lamps.
In a modified and improved version of the up/down table lamp (or floor lamp), the same general principles are applied, but the reflective septum has a special configuration and some details of the mechanical structure of the fixture are changed to provide uniform illumination of a luminous or translucent shade. The lamp still uses two independently controllable and preferably fully dimmable compact fluorescent lamps (CFLs) or less preferably another type of lamp. The reflective septum is in the form of a reflector dish or bowl which is positioned high on the lamp fixture (at the top of the shade) with the upper CFL in the bowl and the lower CFL below it. The lampshade rests on the upper edge of the reflector dish, and is just suspended from the bowl, e.g. by hooks, so it can easily be removed. The top of the shade is flush with the upper edge of the reflector bowl. The light from the upper CFL is directed upwards toward the ceiling, providing indirect lighting; none of the uplight illuminates the shade. The light from the lower CFL is directed downward, illuminating the desk or table it sits on, as well as toward the inner surface of the lampshade, providing an aesthetically pleasing uniform lampshade illumination. The lamp posts which support the CFLs, their electrical sockets, and the reflective dish or bowl, are configured for ease of plugging in or removing the CFLs.